As described for example in Patent Literature 1 listed below and the like, a security printing press employed for printing banknotes such as bank bills and securities such as stock certificates and bond certificates is one which performs offset printing of printing images of a plurality of colors simultaneously on both surfaces of a sheet, by transferring printing images of inks of the respective colors onto two blanket cylinders, which are in contact with each other, from a plurality of inking devices disposed along circumferential directions of the blanket cylinders via corresponding plate cylinders, and by causing the sheet to pass between the blanket cylinders, and which then performs intaglio printing by means of an intaglio printing plate.